The present invention is directed to a hand held testing device having means for selecting independently one of several functions and one of several ranges, respectively, for measuring different electrical quantities within a wide range of magnitudes.
Hand held testing devices are very well known in the art. Usually they are provided with two handles each having a test prong for contacting electrical measuring points. Such hand held testing devices are used for electrical testing purposes; for example, for testing if a voltage at a measuring point is present or not; and for testing short circuits or resistances of electrical connections. For displaying the test result there is provided a display device, such as a light emitting diode. Besides these inexpensive and basic testing devices, there are also others having expanded characteristics and functions. These more reliable testing devices may be able to present a display if such mentioned electrical quantities are within a specific range; however, the presently known hand held testing devices normally are not to be understood as precision measuring devices.
On the other hand, table models for measuring a-c voltages, d-c voltages or resistances have been known for a long time. These measuring devices, which are often called multi-meters, facilitate precision measurements. They are optionally selectable for measuring a specific function within different ranges, as a result. Measurements can be taken upon selecting a suitable measuring range so as to minimize measuring errors. Such table models in comparison to hand held devices have the disadvantage that they are bulky and inconvenient for a variety of applications, especially for outdoor services, such as maintaining and installing electrical equipment. On the other hand, there is a present need among service personnel and others for more sophisticated measuring devices which allow easy handling and give more precise measurement results.